One of the key ingredients in a good news story is dogged, original research. And that’s what lies behind The Post’s story about Sen. Marco Rubio (R-Fla.) and his misleading narrative that he is the child of immigrants who left Fidel Castro’s Cuba.

As we know now, and as Rubio himself has acknowledged, his parents left Cuba on May 27, 1956, some 2 1 / 2 years before Castro came to power and some five years before Castro declared a “socialist revolution” in April 1961.

So how did The Post figure this out? Reporter Manuel Roig-Franzia was on book leave, working on his forthcoming biography of Rubio.

In the course of researching Rubio’s family, Roig-Franzia hoped to find more details about the parents’ life in Cuba and their early years in America. He came across their immigration documents after hours of slogging through microfilm records at the Library of Congress.

He then brought the idea for the story to Post editors; they asked for further research and confirmation. On Oct. 20, when the editors were satisfied the story was ready for publication, Roig-Franzia contacted the senator for comment.

Now this is where the competitive nature of the news business comes in.

On Oct. 19, the St. Petersburg Times published its own story, mainly about the birther movement questioning Rubio’s qualifications to be president or vice president because his parents were not U.S. citizens at the time of his birth in 1971.

But buried deep in the Florida newspaper’s story was an accusation by a prominent figure in that movement, Charles Kerchner, that Rubio’s parents came to the United States in 1956 and not post-Castro, as Rubio had indicated before in interviews and speeches.

The Post knew it had all the documentation to prove that fact, plus more, so the pressure to publish intensified. Editors decided to publish Roig-Franzia’s story online Oct. 20, and in the Oct. 21 paper.

That decision prompted a lot of back and forth between Rubio’s office and Roig-Franzia on Oct. 20: e-mails, phone calls and the written statement that the senator’s office had offered the St. Petersburg Times the day before.

According to Post records, Roig-Franzia’s story with quotes from the written statement was published online at 4:08 p.m. At the moment of publication, Roig-Franzia was at the senator’s office, examining Rubio’s parents’ passports, which showed their trips to Cuba after coming to the United States in 1956, and hoping he might snag Rubio himself for an interview. Rubio’s press secretary, Alex Conant, finally squeezed Roig-Franzia in for a 14-minute interview with the senator. Afterward, Roig-Franzia phoned in quotes from the senator’s office, and the Post updated the story by 4:31 p.m.

Was there a press of time at the last minute to get the story out? Yes, but the fact-checking and documentation had been done. The last piece of the puzzle was Rubio’s comments, and the senator’s office indicated to Roig-Franzia that the senator was busy and there was no guarantee of an interview. The Post initially published with just the statement.

Conant, in a note to me later, objected to the story being published without the senator’s direct quotes. I see his point, and in a perfect world that would be the preferred path. But in the competitive pressures of today’s online and Twitter world, I can’t fault The Post for publishing as it did. And it updated the story with the senator’s quotes less than 30 minutes later.

Rubio’s office objected to The Post saying that the senator “embellished” his family history. Conant said Roig-Franzia should have asked the senator whether he thought he had embellished his life story by saying his parents left Cuba post-Castro. I think that’s a issue more of writing than of interviewing. I think embellishing is the perfect verb for what Sen. Rubio did. His own Senate biography stated that his parents had left Cuba after Castro’s victory, and he changed it as soon as The Post published.

Rubio said he based his story on family lore and that he didn’t have all the documents in his possession. Parents don’t always tell their kids everything about their immigration experience. But if I were running for office, I would want to know, and I wouldn’t say they came after Castro’s rise unless I was sure.

Patrick B. Pexton can be reached at 202-334-7582 or at ombudsman@